DSP: Add ProcessorChain tests

modules/juce_dsp/processors/juce_ProcessorChain.h

@@ -63,64 +63,58 @@ class ProcessorChain
 {
 public:
     /** Get a reference to the processor at index `Index`. */
-    template <int Index>       auto& get()       noexcept { return std::get<Index> (processors).processor; }
+    template <int Index>       auto& get()       noexcept { return std::get<Index> (processors); }
 
     /** Get a reference to the processor at index `Index`. */
-    template <int Index> const auto& get() const noexcept { return std::get<Index> (processors).processor; }
+    template <int Index> const auto& get() const noexcept { return std::get<Index> (processors); }
 
     /** Set the processor at index `Index` to be bypassed or enabled. */
     template <int Index>
-    void setBypassed (bool b) noexcept  { std::get<Index> (processors).isBypassed = b; }
+    void setBypassed (bool b) noexcept  { bypassed[(size_t) Index] = b; }
 
     /** Query whether the processor at index `Index` is bypassed. */
     template <int Index>
-    bool isBypassed() const noexcept    { return std::get<Index> (processors).isBypassed; }
+    bool isBypassed() const noexcept    { return bypassed[(size_t) Index]; }
 
     /** Prepare all inner processors with the provided `ProcessSpec`. */
     void prepare (const ProcessSpec& spec)
     {
-        detail::forEachInTuple ([&] (auto& item, size_t) { item.processor.prepare (spec); }, processors);
+        detail::forEachInTuple ([&] (auto& proc, size_t) { proc.prepare (spec); }, processors);
     }
 
     /** Reset all inner processors. */
     void reset()
     {
-        detail::forEachInTuple ([] (auto& item, size_t) { item.processor.reset(); }, processors);
+        detail::forEachInTuple ([] (auto& proc, size_t) { proc.reset(); }, processors);
     }
 
     /** Process `context` through all inner processors in sequence. */
     template <typename ProcessContext>
     void process (const ProcessContext& context) noexcept
     {
-        detail::forEachInTuple ([&] (auto& item, size_t index) noexcept
+        detail::forEachInTuple ([&] (auto& proc, size_t index) noexcept
         {
             if (context.usesSeparateInputAndOutputBlocks() && index != 0)
             {
                 jassert (context.getOutputBlock().getNumChannels() == context.getInputBlock().getNumChannels());
                 ProcessContextReplacing<typename ProcessContext::SampleType> replacingContext (context.getOutputBlock());
-                replacingContext.isBypassed = (item.isBypassed || context.isBypassed);
+                replacingContext.isBypassed = (bypassed[index] || context.isBypassed);
 
-                item.processor.process (replacingContext);
+                proc.process (replacingContext);
             }
             else
             {
                 ProcessContext contextCopy (context);
-                contextCopy.isBypassed = (item.isBypassed || context.isBypassed);
+                contextCopy.isBypassed = (bypassed[index] || context.isBypassed);
 
-                item.processor.process (contextCopy);
+                proc.process (contextCopy);
             }
         }, processors);
     }
 
 private:
-    template <typename Processor>
-    struct ProcessorWithBypass
-    {
-        Processor processor;
-        bool isBypassed = false;
-    };
-
-    std::tuple<ProcessorWithBypass<Processors>...> processors;
+    std::tuple<Processors...> processors;
+    std::array<bool, sizeof...(Processors)> bypassed { {} };
 };
 
 /** Non-member equivalent of ProcessorChain::get which avoids awkward

modules/juce_dsp/processors/juce_ProcessorChain_test.cpp

@@ -0,0 +1,142 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2017 - ROLI Ltd.
+
+   JUCE is an open source library subject to commercial or open-source
+   licensing.
+
+   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
+   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
+   27th April 2017).
+
+   End User License Agreement: www.juce.com/juce-5-licence
+   Privacy Policy: www.juce.com/juce-5-privacy-policy
+
+   Or: You may also use this code under the terms of the GPL v3 (see
+   www.gnu.org/licenses).
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+namespace juce
+{
+namespace dsp
+{
+
+class ProcessorChainTest : public UnitTest
+{
+    template <int AddValue>
+    struct MockProcessor
+    {
+        void prepare (const ProcessSpec&) noexcept { isPrepared = true; }
+        void reset() noexcept { isReset = true; }
+
+        template <typename Context>
+        void process (const Context& context) noexcept
+        {
+            bufferWasClear = context.getInputBlock().getSample (0, 0) == 0;
+
+            if (! context.isBypassed)
+                context.getOutputBlock().add (AddValue);
+        }
+
+        bool isPrepared     = false;
+        bool isReset        = false;
+        bool bufferWasClear = false;
+    };
+
+public:
+    ProcessorChainTest()
+        : UnitTest ("ProcessorChain", UnitTestCategories::dsp) {}
+
+    void runTest() override
+    {
+        beginTest ("After calling setBypass, processor is bypassed");
+        {
+            ProcessorChain<MockProcessor<1>, MockProcessor<2>> chain;
+
+            setBypassed<0> (chain, true);
+            expect (isBypassed<0> (chain));
+            setBypassed<0> (chain, false);
+            expect (! isBypassed<0> (chain));
+
+            setBypassed<1> (chain, true);
+            expect (isBypassed<1> (chain));
+            setBypassed<1> (chain, false);
+            expect (! isBypassed<1> (chain));
+        }
+
+        beginTest ("After calling prepare, all processors are prepared");
+        {
+            ProcessorChain<MockProcessor<1>, MockProcessor<2>> chain;
+
+            expect (! get<0> (chain).isPrepared);
+            expect (! get<1> (chain).isPrepared);
+
+            chain.prepare (ProcessSpec{});
+
+            expect (get<0> (chain).isPrepared);
+            expect (get<1> (chain).isPrepared);
+        }
+
+        beginTest ("After calling reset, all processors are reset");
+        {
+            ProcessorChain<MockProcessor<1>, MockProcessor<2>> chain;
+
+            expect (! get<0> (chain).isReset);
+            expect (! get<1> (chain).isReset);
+
+            chain.reset();
+
+            expect (get<0> (chain).isReset);
+            expect (get<1> (chain).isReset);
+        }
+
+        beginTest ("After calling process, all processors contribute to processing");
+        {
+            ProcessorChain<MockProcessor<1>, MockProcessor<2>> chain;
+
+            AudioBuffer<float> buffer (1, 1);
+            AudioBlock<float> block (buffer);
+            ProcessContextReplacing<float> context (block);
+
+            block.clear();
+            chain.process (context);
+            expectEquals (buffer.getSample (0, 0), 3.0f);
+            expect (get<0> (chain).bufferWasClear);
+            expect (! get<1> (chain).bufferWasClear);
+
+            setBypassed<0> (chain, true);
+            block.clear();
+            chain.process (context);
+            expectEquals (buffer.getSample (0, 0), 2.0f);
+            expect (get<0> (chain).bufferWasClear);
+            expect (get<1> (chain).bufferWasClear);
+
+            setBypassed<1> (chain, true);
+            block.clear();
+            chain.process (context);
+            expectEquals (buffer.getSample (0, 0), 0.0f);
+            expect (get<0> (chain).bufferWasClear);
+            expect (get<1> (chain).bufferWasClear);
+
+            setBypassed<0> (chain, false);
+            block.clear();
+            chain.process (context);
+            expectEquals (buffer.getSample (0, 0), 1.0f);
+            expect (get<0> (chain).bufferWasClear);
+            expect (! get<1> (chain).bufferWasClear);
+        }
+    }
+};
+
+static ProcessorChainTest processorChainUnitTest;
+
+} // namespace dsp
+} // namespace juce